Enhanced photo-catalytic cells

ABSTRACT

A photo-catalytic cell may produce bactericidal molecules in air by passing air across catalyst coated targets. Ultraviolet (UV) energy may be emitted from a source. A first portion of the UV energy from the source may be applied directly onto the targets. A second portion of the UV energy from the source may be reflected onto the targets.

RELATED APPLICATIONS

This application claims is a continuation of U.S. patent applicationSer. No. 15/144,980 filed on May 3, 2016, which is a continuation ofU.S. patent application Ser. No. 14/065,031 filed on Oct. 28, 2013,which is a continuation of U.S. patent application Ser. No. 13/115,546filed on May 25, 2011 and issued as U.S. Pat. No. 8,585,979 on Nov. 19,2013, and claims the benefit of U.S. Provisional Patent Application No.61/380,462 filed on Sep. 7, 2010, all of which are herein incorporatedby reference.

BACKGROUND OF THE INVENTION

The present invention generally relates to methods and apparatus forproducing an enhanced ionized cloud of bactericidal molecules.

Photo-catalytic cells may be employed to produce bactericidal moleculesin air flow passing through the cells. The cells may be positioned toionize air that may then be directed into an enclosed space or room.Emerging molecules from the cells may have a bactericidal effect onvarious bacteria, molds or viruses which may be airborne in the room ormay be on surfaces of walls or objects in the room.

Typically, such cells may be constructed with a “target material” (orcoated surface(s) surrounding a broad spectrum ultraviolet (UV) emitter.This combination can produce an ionized cloud of bactericidal molecules.The target may be coated with titanium dioxide as well as a few otherproprietary trace elements. As air passes through or onto the target, UVenergy striking the titanium dioxide may result in a catalytic reactionthat may produce the desired cloud of bactericidal molecules within theairflow. These molecules, upon contact with any bacteria, mold or virus,may kill them.

Effectiveness of such photo-catalytic cells may be dependent on theconcentration of the bactericidal molecules which may be produced by thecells. The bactericide concentration level may be dependent on thedegree to which UV energy is applied to the titanium dioxide of thehoneycomb mesh.

As can be seen, there is a need for a system in which a higherproportion of UV energy from a UV emitter (in such a photo-catalyticcell) can be caused to impinge upon the titanium dioxide within thecell.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a photo-catalytic cell with anultraviolet (UV) emitter and catalyst-coated targets may be comprised ofat least one UV reflector configured to reflect UV energy from the UVemitter onto the targets. The rectangular “honeycomb matrix” targetshape shown in the attached FIGS. 1,2 and 3 is just one of manymechanical shapes that could use the proposed “enhanced ionization”technology proposed in this application. The proposed enhancementtechnology consist of reflective surfaces that have the uniquereflective specifications as described in paragraphs 21 thru 26.

In another aspect of the present invention, a method for producingbactericidal molecules in air may comprise the steps of: passing airacross catalyst coated targets; emitting UV energy from a source;applying a first portion of the UV energy from the source directly ontothe targets; and reflecting a second portion of the UV energy from thesource onto the targets.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdrawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a typical photo-catalytic cell inaccordance with an embodiment of the invention in which a typical“honeycomb matrix” is shown as the “target”;

FIG. 2 is a side elevation view of the photo-catalytic cell of FIG. 1;

FIG. 3 is a cross sectional view of the photo-catalytic cell of FIG. 2taken along the line 3-3; and

FIG. 4 is a comparison graph showing a difference in performance of thephoto-catalytic cell of FIG. 1 with and without use of UV reflectors inaccordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplatedmodes of carrying out exemplary embodiments of the invention. Thedescription is not to be taken in a limiting sense, but is made merelyfor the purpose of illustrating the general principles of the invention,since the scope of the invention is best defined by the appended claims.

Various inventive features are described below that can each be usedindependently of one another or in combination with other features.

Broadly, embodiments of the present invention generally providephoto-catalytic cells in which reflectors may be positioned to reflectUV energy and increase a proportion of emitted UV energy that strikestitanium dioxide in the cell at high incident angles.

Referring now to the Figures, it may be seen that an exemplaryembodiment of a photo-catalytic cell 10 may comprise an electronics box12; a light pipe indicator 14; a power cord 16; a chamber 18; honeycombtargets 20; UV reflectors 22-1, 22-2 and 22-3; and a UV emitter or lamp24. The honeycomb targets 20 may be coated with titanium dioxide.

In operation, air may pass across the honeycomb targets 20 while UVenergy may be applied to the target 20 by the lamp 24. A photo-catalyticreaction may take place in the presence of the UV energy. The reactionmay produce bactericidal molecules in the air.

Referring now particularly to FIG. 3, the efficacy of the UV reflectors22-1 may be illustrated. If the reflector 22-1 were not present, anemitted ray 26 might pass through the honeycomb target 20 withoutimpinging on the titanium dioxide. However, when one of the reflectors22-1 is present, an illustrative emitted ray 28-1 of UV energy mayimpinge on the UV reflectors 22-1. The ray 28-1 may be reflected tobecome a reflected ray 28-2. It may be seen that the reflected ray 28-2may impinge on a surface of the honeycomb target 20. It may be seen thata hypothetical unreflected ray 26, which might follow a path parallel tothat of the ray 28-1, might pass through the honeycomb target 20 withoutimpinging on the target 20. Thus, presence of the reflector 22-1 in thepath of the ray 28-1 may result in avoidance of loss of the UV energyfrom the ray 28-1. The reflectors 22-1 may be relatively small ascompared to the size of the honeycomb target 20. The small size (about10% of the size of the target 20) may allow for minimal air flowobstruction. In spite of their relatively small size, the reflectors22-1 may be effective because they may reflect virtually all of the(normally lost) UV energy that is emitted in a direction that is almostorthogonal (i.e., within ±5° of orthogonality) to the outer verticalplane of the honeycomb target 20. Hence, UV energy would pass thru thehoneycomb target without touching the TiO2 surface. But by “reflecting”the UV rays onto the “opposite side” target matrix—that energy could becaptured and utilized so as to add to the total ion count within thedesired cloud of ionized molecules. In other words, the number of ionscreated by any incoming UV ray is proportional to the sine of theincident angle (Theta) between the UV ray path and the TiO2 surface thata given ray is impacting.

At theta=90 deg Sine (90)=1 Maximum energy gathered

At theta=0 deg Sine (0)=0 Minimum energy gathered

Reflectors 22-3 may be interposed between the lamp 24 and walls of thechamber 18. UV energy striking the reflectors 22-3 may be reflected ontothe honeycomb target 20. Thus presence of the reflectors 22-3 may resultin avoidance of loss of UV energy that might otherwise be absorbed ordiffused by walls of the chamber 18. Similarly, reflectors 22-2 may beplaced in corners of the chamber 18 to reflect UV energy onto thehoneycomb target 20.

The reflectors 22-1, 22-2 and/or 22-3 may be constructed from materialthat is effective for reflection of energy with a wavelength in the UVrange (i.e., about 184 nanometers [nm] to about 255 nm). While softmetals such as gold and silver surfaces may be effective reflectors forvisible light, their large grain size may make them less suitable thanmetallic surfaces with a small grain size (i.e., hard metals). Thus,hard metals such as chromium and stainless steel and other metals thatdo not readily oxidize may be effective UV reflectors and may beparticularly effective for use as UV reflectors in the photo-catalyticcell 10. Material with a UV reflectivity of about 90% or higher may besuitable for use in the reflectors 22-1, 22-1 and 22-3. Lowerreflectively produces lower effectiveness. To achieve the level ofreflection required, it may be necessary to “micro-polish or buff” aselected materials reflective surface to achieve the specificationsdefined in para 22]-24] below.

Advantageously, reflecting surfaces of the reflectors 22 should beelectrically conductive. Specifically, outer surface coatings (added foroxidation protection) like glass, clear plastics, clear anodization(i.e. non-conductive) may diminish (considerably) any performanceenhancement of the photo-catalytic cell 10.

Also it is important that reflecting surfaces of the UV reflector 22produce surface specular reflection. (Specular reflection being a“mirror-like reflection” of light—in which a single incoming light rayis reflected into a single outgoing direction) Specular reflection isdistinct from “diffuse” reflection where an incoming light ray isreflected into a broad range of directions. Diffuse reflection maydiminish performance enhancement of the photo-catalytic cell 10.

In an exemplary embodiment of the photo-catalytic cell 10, thereflectors 22-1, 22-2 and 22-3 may be chromium-plated plastic.Chromium-plated plastic may be a desirably low cost material with adesirably high degree of reflectivity for UV energy. So called “softchrome” such as the plating used to produce a mirror-like finish that isseen on automobile chromed surfaces may be advantageously employed.

It may be noted that there may be other cell shape designs which are notrectangular. For example, the cell 10 may be circular, tubular, or mayhave an otherwise complex shape. For these non-rectangular shaped cells,an optimum reflector design may be curved or otherwise non-flat inshape.

It should be understood, of course, that the foregoing relates toexemplary embodiments of the invention and that modifications may bemade without departing from the spirit and scope of the invention as setforth in the following claims.

1. An apparatus for ionizing air, the apparatus comprising: a firsttarget including: an inner side arranged to receive ultra-violet (“UV”)energy from a UV emitter, an outer side that abuts a region where anairflow is unobstructed, a plurality of passages extending continuouslybetween the inner side and the outer side, and a photo-catalytic coatingon the plurality of passages, wherein the photo-catalytic coatingcomprises titanium dioxide; a first reflector configured to reflect UVenergy from the UV emitter towards the photo-catalytic coating of thefirst target, wherein the first reflector is a specular UV reflector;and wherein the first target is arranged to: receive, through the innerside and at the photo-catalytic coating, UV energy from the UV emitterand UV energy from the first reflector, wherein incident angles ofspecularly reflected UV ray paths received from the first reflector aregreater than incident angles of UV ray paths received directly from theUV emitter, ionize air in response to the received UV energy, and passthe airflow from the inner side and through the plurality of passages tocarry the ionized air away from the outer side.